1. Field of the Invention
The present invention concerns a swivelling handle or head having three axes of rotation and intended to be mounted at the end of an electrically controlled industrial robot arm.
2. Description of the Prior Art
The industrial robots used to meet the needs of automation of the tools of production, in particular mass production, may include, depending on their configuration, a translational unit or arm having a sliding carriage. The end of the arm or of the carriage is equipped with a swivelling module or handle having three axes of rotation. The handle may be equipped with various tools making it possible to automate a large number of manufacturing and transfer operations, such as welding, cutting of parts, handling, etc.
Until now, control of the various rotational movements about the three axes of the swivelling handle was achieved by hydraulic means powered by a single power station or by electrical means including one or more electric drive motors mounted in the arm or the support carriage of the handle. Means of transmission generally including gears, drive chains or belts were thus provided between the arm and the handle. Such an arrangement causes operating play to appear between the various parts, and in particular sliding play by use of belt drives. In addition, the use of a control motor common to the handle's three axes of rotation, equipped with a single coding system and an initial position detection system also common to the three axes of rotation, is the source of practical difficulties. In particular, the handles of the prior art can not easily be replaced by handles with a different structure for modification of the tasks to be performed or adapted to robots having various architectures.